Curtain air bags are designed to primarily protect passenger head by an air bag cushion expanded by the gas exerted by an explosion of an inflator in the event of side collision.
Different passengers have different physical characteristics, including height. Particularly, there is a significant height difference between children and adults. As a result, in order to protect the heads of children, it is required to increase the length downward of an air bag cushion to unfold down.
However, as the length of an air bag cushion increases, the volume of a curtain air bag largely increases downward. This makes it difficult to mount a curtain air bag in a narrow space between the chassis and the head lining.
There is thus a need for an improved curtain air bag device that can protect passengers with different heights by automatically shifting unfolded-positions of an air bag cushion of a curtain air bag in accordance with passenger heights.